Dragutin Culinovic <dragutin.culinovic at fsb.hr> wrote in message news:<bo7o7e$af9$1 at smc.vnet.net>...
> How can I to multiply enumerated list of rows of an matrice on following
> way:
> To multyply each row (except rows a,b and c)of matrice A withe row a of
> the same matrice, and replace that row (not a row) with result.
>
> rows b and c are last rows, row a is any row in the range 1->b(exclusive)
>
> THX
Example of solution with your notation :
In[1]:= m = {{m11,m12},{m21,m22},{m31,m32},{m41,m42},{m51,m52}};
In[2]:= a=2; b=4;
In[3]:=MapAt[#*m[[a]]&, m, Table[{i},{i, a+1, b-1}]]
Out[3]={{m11,m12},{m21,m22},{m21 m31,m22 m32},{m41,m42},{m51,m52}}
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jcp